Remove on-disk WM trace logging

Currently WM traces can be continuously stored to disk
(non-continuous mode), without any size limit.

- Remove the non-continuous mode
- Create a parameter to choose between per trace and per transaction
logging
- Create a parameter to choose the log level
- Add a help to explain the parameters

To enable select log per frame/transaction:
- adb shell cmd window tracing frame/transaction

To change the log level:
- adb shell cmd window tracing level critical/trim/all

Test: Flash a device. Change log levels and frequency. Check if log is
correct on Winscope
Change-Id: If755460ddf80cef4f9d3e57b5a6b72a6599ea87a